Field of the Invention
The invention relates to a method for moulding and surface processing electronic components by successive processing steps. These processing steps comprise —among others —A) the attachment of a grid of electronic components on a carrier; B) the placing of a foil against the side of the electronic components opposite to the carrier; C) the enclosure of the foil covered electronic components on the carrier with a mould cavity; D) the feeding to the mould cavity of an encapsulating material; E) the at least partial hardening of the encapsulating material fed to the mould cavity; and F) removing from the mould cavity the partial encapsulated electronic components attached to the carrier.
Description Of Related Art
During the encapsulation of electronic components mounted on a carrier, and more particularly the encapsulation of semiconductor circuits (chips)/integrated circuits (IC's), use is usually made according to the prior art of encapsulating presses provided with two mould halves, into at least one of which is recessed one or plural mould cavities. After placing the carrier with the electronic components for encapsulating between the mould halves, the mould halves may be moved toward each other, e.g. such that they clamp the carrier. A, normally heated, liquid encapsulating material may then be fed to the mould cavities, usually by means of transfer moulding. As an alternative it is also possible to bring the encapsulating material as a granulate in the mould cavity in which case the components to be moulded are pressed into the moulding material; such compression moulding process is an alternative for transfer moulding. Applied as encapsulating material is epoxy (also referred to as resin) which is generally provided with filler material. After at least partial (chemical) curing of the encapsulating material in the mould cavity/cavities, the carrier with encapsulated electronic components is taken out of the encapsulating press. And the encapsulated products are separated from each other during further processing. The use of foil is to screen or cover a part of the electronic components to be covered with the foil and thus to prevent a part of electronic component to be covered by the encapsulating material. The partial covered product (not over moulded products are also referred to as “bare die” products) can be used in various applications; like for instance various types of sensor components or heat dissipating components. This method of moulding is practised on large industrial scale and enables well controlled moulding of partially uncovered electronic components. A problem during the subsequent processing of the partial moulded and separated electronic components is that the accuracy of the dimensions of the moulded product is not fully controllable, among others due to the heating and cooling that takes place during the moulding process.
The present invention has for its object to provide an alternative method and device with which the advantages of the prior art method of partial moulding of electronic components are maintained but that enable better/more accurate processing of the partial moulded electronic components in subsequent processing steps.